Fuel pump



Nov. 6, 1962 s. a. KEEVIL, JR

FUEL PUMP Filed Feb. 23, 1960 JNVENTOR. SIDNEY G. KEEVIL. JR

wwm

ATTORNEY United States atet Patented Nov. 6, 1962 Free,

'of New Jersey Filed Feb. 23, 1960, Ser. No. 10,504 6 Claims. (Cl. 103-38) This invention relates to fuel pumps and, more particularly, to engine driven diaphragm pumps adapted to continuously supply fuel from a fuel tank to a carburetor in sufficient quatities to satisfy engine requirements.

Engine driven diaphragm fuel pumps have heretofore been provided with a rocker arm pivotally mounted intermediate its ends, one end of the arm being disposed to engage a pull rod secured to the diaphragm, and the other end of the arm being biased against a cam on an engine driven camshaft by means of a compression spring interposed between said other end of the arm and a rocker arm housing. During operation of the pump, the cam acts through the rocker arm and pull rod to move the diaphragm in one direction to draw fuel from the tank past an inlet valve into a pump chamber, the diaphragm being moved in the opposite direction by a compression spring to discharge fuel from the pump chamber past an outlet valve to the carburetor at a substantially constant pressure.

An object of the present invention resides in the provision of an engine driven diaphragm fuel pump wherein the rocker arm biasing spring is mounted within the spring housing and acts through the pull rod to bias the rocker arm against the engine driven cam.

Another object of the invention resides in the provision of a fuel pump wherein the biasing spring acts to bias the rocker arm transversely of the pivot pin to thereby reduce noise due to wear of the pivot pin and the pin receiving hearings on the rocker arm.

A further object of the invention resides in the provision of a fuel pump wherein the biasing spring is disposed to exert its maximum force in biasing the rocker arm against an engine driven cam.

Another object of the invention resides in the provision of a fuel pump wherein the usual spring retaining tang is omitted from the rocker arm.

Another object of the invention resides in the provision of a diaphragm fuel pump having a lost motion connection between the diaphragm and the pull rod.

The invention embodies other novel features, details of construction and arrangement of parts which are hereinafter set forth in the specification and claims and illustrated in the accompanying drawing, forming part thereof, wherein:

FIG. 1 is a vertical section illustrating a fuel pump embodying features of the invention, the pump being shown as applied to an internal combustion engine to supply fuel from a tank to a carburetor.

FIG. 2 is an enlarged fragmentary section, partly in elevation, illustrating the lost motion connection between the diaphragm and the pull rod.

FIG. 3 is a detail section taken along the line 33 which extends through coaxial bearings 77 in the side flanges 88 of the rocker arm, the ends of the pin being securely mounted on the side walls of the housing 2. The outer end 9 of the rocker arm 4 is adapted to slidably. engage a cam 11 provided on a camshaft 12 driven by the engine.

The inner end 13 of the rocker arm 4 is bifurcated to receive one end of a pull rod 14 having a head 16 and washers 17 thereon for engagement by the rocker arm. The pull rod 14 extends into a spring housing 18 which is preferably formed integral with the rocker arm housing 2 and provided with an annular shoulder 19 to engage the marginal portion of a flexible oil sealing member 21 having a central aperture to snugly receive the pull rod. A spring seat member 22 is secured to the end of the pull rod 14 for engagement by a helical rocker arm biasing spring 23 seated on a spring retainer 24 which, in turn, is seated against the marginal portion of the sealing member 21, said spring being normally under compression to maintain the outer end of the rocker arm in engagement with the cam 11.

The spring seat member 22 is formed with diametrically opposed slots 26-26 to receive arms 27-2'7 formed on a connecting link 28, each arm being formed at its end with laterally extending ears 2929 for abutting engagement against the spring seat member to limit movement of the link 28 in one direction relative to the pull rod. The link 28 is secured to the central portion of a flexible pump diaphragm 30 by means of a rivet 31 which also serves to secure backing plates 32 and 33 against opposite sides of the diaphragm. The spring seat member 22 and connecting link 28 thus provide a lost motion connection between the pull rod 14 and the pump diaphragm 30.

The marginal portion of the pump diaphragm 30 is clamped between annular flanges 36 and 37 on the spring housing and a valve casing 38, respectively, by means of cap screws 39. The diaphragm 30 and valve casing 38 define a pump chamber 41. The valve casing 38 is provided with inlet ports 42 and outlet ports 43 which are normally closed by spring biased check valves 44 and 46, respectively. A cover 47 is bolted to the valve casing 38 with a resilient gasket 48 therebetween to define a fuel inlet chamber 49 and a pulsation chamber 51. The cover 47 is provided with a fuel inlet 52 connected to a fuel tank T by means of a conduit 53, and the valve casing 38 is provided with a fuel outlet 54 connected to a conventional carburetor C by means of a conduit 56. A diaphragm biasing compression spring 57 is seated on the spring retainer 24 to engage and bias the diaphragm upwardly toward the pump chamber 41 to discharge fuel therefrom on the discharge stroke of the pump.

During operation of the fuel pump to supply fuel from the tank T to the carburetor C, the rocker arm 4 is first pivoted in a clockwise direction on the intake stroke, as viewed in FIG. 1, to pull the pull rod 14 and diaphragm 30 downwardly to draw fuel from the tank T past the intake valve 44 into the pump chamber 41.

On the discharge stroke of the pump,'the rocker arm biasing spring 23 acts through the spring seat member 22 and pull rod 14 to pivot the rocker arm 4 in a counterclockwise direction, as viewed in FIG. 1, to maintain the outer end 9 of the rocker arm in abutting engagement against the cam 11. The diaphragm biasing spring 57 then acts to urge the diaphragm 30 upwardly to force fuel from the pump chamber 41 past the outlet check valve 46 into the pulsation chamber 51 and thence through the outlet 54 and conduit 56 to the carburetor.

Throughout the operating cycle of the fuel pump, it will be noted that the rocker arm biasing spring 23 acts to exert an upward force on the rocker arm 4, as viewed in FIG. 1, to maintain the bearings 77 in contact at all times against the underside A of the pivot pin 6 to thereby eliminate the slapping or clicking noise usually associated with conventional diaphragm fuel pumps when the pivot pin and rocker arm bearings become worn, as pointed out in US. Patent 2,919,654 issued January 5, 1960 to Alfred C. Korte.

FIG. 4 illustrates a modified form of the invention wherein the pull rod 55 is provided with a spring seat portion 58 for engagement by the rocker arm biasing spring 23, the rod having an axial bore 59 to receive the lower end of a connecting link 61 formed with a slot 62 to receive a pin 63 mounted at its ends in the spring seat portion 58. In this form of the invention, the upper end of the link 61 may be peened over at 64 to secure the link, backing ptlates 32-33, and diaphragm 30 in assembled relationship. This embodiment of the invention is other wise similar in construction and operation to the form illustrated in FIGS. 1 and 2.

Certain structures have been shown and described herein which will fulfill all the objects of the present invention, but it is contemplated that other modifications will be obvious to those skilled in the art which come within the scope of the invention as defined by the appended claims.

I claim:

1. A fuel pump for an internal combustion engine having a rotatable pump actuating cam, said fuel pump comprising a housing having a pumping chamber therein, a reciprocable pumping element mounted in said housing to move fluid through said pumping chamber, a pull rod in said housing, a lost motion connection between said pull rod and pumping element, a rocker arm pivotally mounted intermediate its ends in said housing, one end of said arm adapted to engage said cam and the other end engaging said pull rod, whereby said pumping element may be pulled in one direction to draw fuel into said pumping chamber responsive to rotation of said cam, a first helical compression spring engaged between said housing and said pull rod to bias said one end of the rocker arm against said cam, a second helical compression spring engaged between said housing and said pumping element to urge said element in a direction to discharge fuel from said pumping chamber responsive to rotation of said cam, said first and second springs being coaxial with said pull rod, and a spring retainer member mounted on said housing for engagement by said first and second springs.

2. In a fuel pump for an internal combustion engine having a rotatable pump actuating cam, a housing having a pumping chamber therein, a reciprocable pumping element mounted in said housing to move fluid through said pumping chamber, a pull rod in said housing, a lost motion connection between said pull rod and pumping element, a rocker arm pivota'lly mounted intermediate its ends in said housing, one end of said arm engaging said cam and the other end engaging said pull rod, whereby said pumping element is pulled in one direction to draw fuel into said pumping chamber responsive to rotation of said cam, a first helical compression spring engaged between said housing and said pull rod to bias said end of the rocker arm against said cam, a second helical compression spring engaged between said housing and said pumping element to urge said element in a direction to discharge fuel from said pumping chamber responsive to rotation of said cam, said first and second springs being coaxial with said pull rod, a spring retainer member mounted on said housing for engagement by said first and second springs, and a flexible gasket engaged between said spring retainer member and housing and provided with a central aperture to receive said pull rod.

3. A fuel pump for an internal combustion engine having a rotatable pump actuating cam, said fuel pump comprising a housing having a pumping chamber therein, a

reciprocable pumping element mounted in said housing to move fluid through said pumping chamber, a pull rod in said housing, a lost motion connection between said pull rod and pumping element, a rocker arm pivotally mounted intermediate its ends in said housing, one end of said arm adapted to engage said cam and the other end engaging said pull rod, whereby said pumping element may be pulled in one direction to draw fuel into said pumping chamber responsive to rotation of said cam, a first helical compression spring engaged between said housing and said pull rod to bias said one end of the rocker arm against said cam, a second helical compression spring engaged between said housing and said pumping element to urge said element in a direction to discharge fuel from said pumping chamber responsive to rotation of said cam, said pumping element comprising a flexible diaphragm forming one wall of said pumping chamber, said lost motion connection comprising a head on said pull rod engaged by said first spring, and a link secured to said diaphragm for engagement with said head.

4. A fuel pump for an internal combustion engine having a rotatable pump actuating cam, said fuel pump comprising a housing having a pumping chamber therein, a reciprocable pumping element mounted in said housing to move fluid through said pumping chamber, a pull rod in said housing, a lost motion connection between said pull rod and pumping element, a rocker arm pivotally mounted intermediate the ends thereof in said housing, one of said ends of said rocker arm adapted to engage said cam and the other of said rocker arm ends engaging said pull rod, whereby said pumping element is pulled in one direction to draw fuel into said pumping chamber responsive to rotation of said cam, a first helical compression spring engaged between said housing and said pull rod to bias said one end of the rocker arm against said cam, a second helical compression spring engaged between said housing and said pumping element to urge said element in a direction to discharge fuel from said pumping chamber responsive to rotation of said cam, said pumping element comprising a flexible diaphragm forming one wall of said pumping chamber, said lost motion connection comprising a spring seat member on said pull rod engaged by said first spring, a link secured to said diaphragm for engagement with said seat member, said link having spaced arms straddling said seat member, and ears on the ends of said arms for abutting engagement with said seat member.

5. A fuel pump for an internal combustion engine having a rotatable pump actuating cam, said fuel pump comprising a housing having a pumping chamber therein, a reciprocable pumping element mounted in said housing to move fluid through said pumping chamber, a pull rod in said housing, a lost motion connection between one end of said pull rod and said pumping element, a rocker arm pivotally mounted intermediate its ends in said housing, one end of said rocker arm adapted to engage said cam and the other end of said rocker arm engaging the other end of said pull rod, whereby said pumping element is pulled in one direction to draw fuel into said pumping chamber responsive to rotation of said cam, a first helical compression spring engaged between said housing and said pull rod to bias said one end of the rocker arm against said cam, a second helical compression spring engaged between said housing and said pumping element urging said element in a direction to discharge fuel from said pumping chamber responsive to rotation of said cam, said pumping element comprising a flexible diaphragm forming one wall of said pumping chamber, said lost motion connection comprising a head on said one pull rod end engaged by said first spring, said one pull rod end formed with a bore coaxial therewith, a link secured to said diaphragm and having one end thereof positioned within said bore for telescopic engagement with said head, said link having a slot therein, and a pin mounted on said head and extending through said slot.

6. A fuel pump for an internal combustion engine having a rotatable pump actuating cam, said fuel pump comprising a housing having a pumping chamber therein, a reciprocable pumping element mounted in said housing to move fluid through said pumping chamber, a pull rod in said housing, means forming a lost motion connection between one end of said pull rod and said pumping element, a rocker arm pivotally mounted intermediate its ends in said housing, one end of said rocker arm adapted to engage said cam and the other end thereof engaging the other end of said pull rod whereby said pumping element is pulled in one direction to draw fuel into said pumping chamber responsive to rotation of said cam, a first helical compression spring engaged between said housing and said pull rod to bias said one end of the rocker arm against said cam, a second helical compression spring engaged between said housing and said pumping element urging said pumping element in a direction to discharge fuel from said pumping chamber responsive to rotation of said cam, said pumping element comprising a flexible diaphragm forming one wall of said pumping chamber, said lost motion connection comprising a link secured to said diaphragm and having a slot therein, a pin mounted on said one pull rod end and extending through said slot, and backing plates on opposite sides of said diaphragm, said link including means clamping said backing plates against said diaphragm.

References Cited in the file of this patent UNITED STATES PATENTS 1,749,367 Zubaty Mar. 4, 1930 1,919,040 Rockwell July 18, 1933 1,919,496 Babitch July 25, 1933 1,981,667 Rockwell Nov. 20, 1934 

